NASA to begin attempts to free Spirit

Spirit has been stuck in martian sand since April 23.

Researchers expect the extraction process -- to begin Monday -- to be long and the outcome uncertain.

"This is going to be a lengthy process, and there's a high probability attempts to free Spirit will not be successful," said Doug McCuistion, director of the Mars Exploration Program." After the first few weeks of attempts, we're not likely to know whether Spirit will be able to free itself."

Spirit has six wheels for roving Mars. The first commands will tell the rover to rotate its five working wheels forward approximately six turns. Engineers anticipate severe wheel slippage, with barely perceptible forward progress in that initial attempt. Since 2006, Spirit's right-front wheel has been inoperable, possibly because of wear and tear on a motor.

"Mobility on Mars is challenging, and whatever the outcome, lessons from the work to free Spirit will enhance our knowledge about how to analyze martian terrain and drive future Mars rovers," McCuisition said.

Spirit and its twin rover landed on Mars in January 2004. They have explored the planet for five years, far surpassing their original 90-day mission.

Copyright 2009 by United Press International.